The present invention relates generally to monitoring the dew point of a fuel gas in a combustion turbine. Specifically, the present invention relates to a method and system for regulating the temperature of a fuel gas mixture used by combustion turbines by monitoring the dew point of the fuel gas mixture in the combustion chamber.
Many gas fired turbines require 50 degrees (Fahrenheit) of xe2x80x9csuperheatxe2x80x9d to operate under normal conditions. xe2x80x9cSuperheatxe2x80x9d is heat over and above the dew point of the gas. Dew point is the temperature at which a given gas will be saturated with a liquid, it is the temperature at which the liquid will begin to condense. Many power producers heat their fuel gas regardless of the temperature to insure that it meets the 50-degree Fahrenheit minimum requirement.
As a result, several different systems have been developed to ensure that the fuel gas is heated by at least 50 degrees Fahrenheit above the dew point temperature. These systems typically waste energy by heating the fuel stream in excess of the 50-degree Fahrenheit minimum.
In light of the shortcomings of known systems, a need exists for a more efficient system for superheating the fuel gas stream. The present invention provides a dew point monitoring system. A preferred embodiment of the present invention is particularly useful to minimize the energy load of superheating a fuel gas stream. A preferred embodiment of a system of the present invention may also include the basic controls, instrumentation, and piping for the system to work together.
In a preferred embodiment of the present invention, the pressure of a flow of fuel gas is reduced at a pressure reduction station prior to entering an aerosol interception and removal system. In the aerosol interception and removal system particulate matter may be filtered out and liquid droplets may be coalesced. Upon exiting the aerosol interception and removal system, a dew point monitoring device sends a signal to the heating system. The filtered flow of fuel gas is then directed to a heating system where the temperature of the fuel gas is regulated. The heating system receives information from the dew point monitoring system such that the heating system may adjust the temperature of the fuel gas flow within the permissible range necessary for operation of the combustion turbine. The flow of the heated flow of fuel gas may then be regulated at a flow metering station. The heated flow of fuel gas is then sent to a combustion turbine""s combustion chamber.
In addition to the novel features and advantages mentioned above, other objects and advantages of the present invention will be readily apparent from the following descriptions of the drawings and preferred embodiments.